PRACTICAL ORGANIC CHEMISTRY
forms of ketoximes. The two isomeric phenyltolylketoximes
yield two different amides,
QH5. C. CGH4. CI I, C8H0. C. C8H4CH3
II -> I
Toluic anilide, on hydrolysis, forms toluic acid and aniline,
whereas benzoic toluide yields benzoic acid and toluidine. It
follows therefore that, in the original compound, the first con-
tains the hydroxyl nearer the phenyl group and the second
nearer the tolyl group.
For further details on the stereoisomerism of nitrogen com-
pounds, the text-book must be consulted.
Diphenylmethane.—This reaction is analogous to that of
aluminium chloride on a mixture of benzene and benzyl chloride
referred to in the notes on Prep. TOO, p. 310. The reaction is
also effected by the use of zinc dust or finely-divided copper
Triphenylmethane.--This is another example of the
" Friedel-Crafts'" reaction, which has already been referred to
in the notes on Prep. 100, p. 309.
Thfc synthesis of pararosaniline from triphenylmethane is one
which has gone far to solve the problem of the constitution of
the important class of triphenylmethane colouring matters.
Rosaniline or magenta was originally obtained by oxidising
with arsenic acid a mixture of aniline with o- and p-
toluidine. The product was then lixiviated and treated with
common salt, which converted the arsenate into the hydro-
chloride of rosaniline. Pararosaniline was prepared in a similar
way from a mixture of aniline and /-toluidine. The series